SLEEPING
JON IS AN OLD MAN WHO MAKES SURE THAT HE IS IN BED IMMEDIATELY BY 11 AT THE LATEST
THIS VICTORIAN GRANDPA IN THE BODY OF AN EARLY 30-SOMETHING YEAR OLD CAN'T FATHOM BEING AWAKE AT 3 IN THE MORNING ARE YOU INSANE
Liss is probably up playing video games unless Jon wakes up to use the bathroom and yells at them to get to bed LOLL (or he has a nightmare and comes to watch Liss play games all night-)

UNLESS YOU SPECIFICALLY MEANT SOMETHING THAT /WAKES THEM BOTH UP/ AT 3AM I may have misread this ask my love I'm so sorry I'm stupid ahioSDHIH
Some contenders for THAT would be:
* Tim drunk texting them memes at 3AM (or straight up calling Liss to come hang out or something. "Tim it's 3AM and I'm sleeping-" "So?" "Jon is also here and sleeping?" "He can come too! We're young get your butts up let's go-")
* Corvo, their cat, climbing up and falling off the Bi flag Liss has hanging in their living room because Corvo Knows What They Are
* Daisy standing at the end of their bed in season 4 telling them both she threw up
* Helen standing at the end of their bed in season 4 telling them both she threw up
* Liss being woken up by Jon at 3AM because The Eye possessed him for a second and he NEEDED to let Liss know either "The oldest working clock in the world is the Salisbury Cathedral Clock in Salisbury, England. This mechanical clock dates all the way back to 1386. (The Salisbury Clock was actually replaced in 1884, and the original model wasn't rediscovered until 1929" OR that some random kid Liss knew in 5th grade was just diagnosed with a rare tongue disease that only happens in people with- No Liss listen you NEED to know this okay-