Its 300 feet in the air though, you can come up with the ideas of ropes, parachutes, slides etc but it has to be something that someone who is injured, old or otherwise incapable is able to use in an emergency. Imagine if they just had a 300 foot rope and a couple people plummeted to their death trying to escape. The negligence payout on something like that would be enormous. Thus they have the slide chute with netted sides so you cant fall out. On my job site we have people working at extreme heights wearing safety harnesses. If they fall they will be protected but are then stuck there and will suffer circulation cutoff injuries if they hang too long. The plant has a high angle rescue team that is able to be on site anywhere in the plant in 3 minutes to get them down. That isnt available in a an offshore rig so they have to come up with something like that hamster chute to deal with it.