The first lift that descends to the lights out w/ skaarj area can be blocked indefinitely. Immediately beneath the lift there is a small recession into the brick wall containing some ammo. It's big enough to let a player stand inside. Here, a player can throw a weapon (an automag is provided at the beginning of this map) and have its collision cylinder extend in the path of the lift, blocking it. The player must pick up the weapon and throw it again every few seconds to prevent it from disappearing. This could potentially be a permanent block if a naliseed is thrown instead of a weapon.
Lift After Arrow Buttons
Above this lift are two wooden crates. Each of these contains a health pickup. If the player pushes these down onto the lift (note: raise the lift first so they don't break) and then breaks them halfway off the lift, it's possible to get the lift in a jammed state. The behavior of the health pickups is fairly unpredictable, but it has been proven that one can get the lift jammed above its bottom position. If jammed in such a manner it is impossible for players to board the lift.
If a player had jumpboots it would be possible to time a jump (while damaged) to pick up the health when it's in the aforementioned state. It would be difficult but theoretically possible to unblock the mover like this. This has yet to be demonstrated. More importantly, jumpboots can be used to bypass this part of the level entirely, rendering the block ineffective.