What affects the chance to get an escape mission?

So far I know that doing a mission in full stealth and the expert driver asset prevent escapes completely.

Added Inside Man Assets on almost all levels so that you can buy a EXPERT DRIVER that 100% takes away the Escape. -- source

What else affects escapes? Does difficulty have a part in this? Is it ever guaranteed to get an escape?

Solution 1:

While there are currently no exact numbers on what causes an escape missions, I've noticed the following by observing when we get escape missions after completing the main segment of the mission:

• If no alarms are ever set off, there is no escape
• If you have the Expert Driver asset, there is no escape
• If you leave during an assault, there seems to be a very high (practically guaranteed) chance of an escape
• If you leave after an assault, before the next assault, there seems to be a reduced chance of escape
• If you leave after killing all enemies in a wave, outside of an assault phase, there seems to be a reduced chance of an escape
• Once you have set off an alarm, killing civilians will increase the chance of an escape mission

Ultimately, escape missions are there to prevent the "quick and dirty grind" - if you want to go in loud and don't prepare properly, expect an escape to happen.

Solution 2:

From The Long Guide by Frankelstner:

Heists usually have a chance of about 10% to 25% to have an escape level if alarm went off (if the heist does support escapes at all). Every dead civilian adds 5% to this chance. The expert driver asset removes the chance entirely. If there are several possible escapes, they are all equally likely to occur.

The levels usually enable escapes immediately when the alarm goes off. Once all players enter the escape zone (2 seconds before the level actually finishes), the game checks if escapes are enabled at all and if they are, the escape chance is evaluated. If alarm goes off after all players have entered the escape zone, the stealth bonus is lost, but there will not be an escape. Day 1 of Framing Frame and day 2 of Rats enable escapes only after a delay: There is no escape as long as all players enter the escape zone before that.

As for the actual escape data:

• Trustee Bank: 15% chance on gold and cash, 5% else. Possible escapes: Cafe, Park, Street
• Jewelry Store: 25%/27%/32%/36% chance on N/H/VH/OK+DW difficulty. Possible escapes: Cafe, Park, Street
• Ukrainian Job: 30%/33%/35%/37% chance on N/H/VH/OK+DW difficulty. Possible escapes: Cafe, Park, Street
• Four Stores: 30% chance. Possible escapes: Cafe, Park, Street
• Diamond Store: 10% chance. Possible escapes: Cafe, Park, Street
• Framing Frame day 1: 25% chance. Possible escapes: Cafe, Park. Escape chance enabled 25 seconds after the alarm.
• Framing Frame day 2: 24% chance. Possible escapes: Overpass, Park
• Nightclub: 25% chance (killing civilians has no effect). Possible escapes: Cafe, Garage, Overpass, Park
• Rats day 1: 45% chance when lab not exploded, else 100%. Possible escapes: Garage, Overpass. The chance is actually 25%, but the 4 cooks killed at the beginning count as civilians.
• Rats day 2: 25% chance, enabled once police arrives (80 or 90 seconds after the alarm if no police ambush, else 0 seconds). Possible escapes: Overpass, Garage (if there was an escape on day 1, choose the other one)
• Transport Harbor: 15% chance. Possible escapes: Garage, Overpass
• Transport Crossroads: 15% chance. Possible escapes: Cafe, Street
• Transport Park: 15% chance (killing civilians has no effect). Possible escapes: Cafe, Overpass, Street
• Transport Downtown: 10% chance. Possible escapes: Cafe, Park
• Transport Underpass: 10% chance. Possible escapes: Park, Street

Notes on the escapes:

• Overpass: Bain announces at the start whether to expect a van or helicopter. There is only one possible van location, at the parking lot.
• Garage: After going up the staircase, stick to the left and jump over the barrier. Hug the wall and cross over to the other side. After a few more turns to the left there will be a door to the left. Open it and you are at the van.
• Park: The van only arrives in streets which are not blocked by police vehicles.
• Cafe: The map has three possible van locations, but the location closest to your spawn is disabled.

To add to this, contrary to popular belief, leaving during or after an assault does not affect the chances of getting an escape mission.