Medkiting into the armory help needed

[MrUnknown625]

So I have tried for the past two hours to try to use the medkit trick to get into the crimson armory to do the glitch like christmas mission. I have 54 inventory slots free and lay down the kits but when I return as fast as I can with lilith they arleady start disappearing. Any way to make them stay longer. I saw a youtube video and it said they should stay for 10-15min but mine clearly dissappear before that.

[Terminator]

Nope, if this trick doesn't work, then try and find someone online that hasn't started/handed in this mission yet and finish it that way .