The Special Effects co-ordinator James Sled and the Special Effects key Jordan Kean can be seen in the "birthday scene" standing in as "celebratory friends".
During the Police Station "escape scene", green smoke canisters were used to mimic gas bombs. The scene involved Police officers to run out from the smoked out building and open fire on the "escapees" The entire front of the building was glass windows with one glass door. The smoke was so dense that during the take the first "Police Officer" ran directly into the glass windows mistaking it for the door. He was so disoriented that when he finally emerged he did not know which direction to face.
Speaking of timelines, 88 is the speed in miles per hour that the DeLorean in the Back to the Future series, also featuring Christopher Lloyd, had to attain in order to achieve time travel.