drug screen 2morro

ok heres my plan and sum questions

im getting clean urine 2night from my sis and will use it 2morro @ 2-3
--will i be fine leaving it in a closed container up until the test?
--should i store it in the fridge?
--or should i get it in the morning b4 she goes to work?

so the container will be chillen at my house till i get home from school at about 1
and i go in at 2 ill prolly be sitting there for an interview and she told me i gotta watch a safety movie or sumthin but im not sure if thats b4 or after the drug screening.

so heres my plan
i get outta school go home and get it then leave at 2...ill check the temp b4 i leave the house and put it on my dash board and turn the defrosters on high till i get there (i was told this was a good way to keep it warm...but will it make it too warm?) then ill take the temp again b4 i get outta my car and see what its at....then put it in my undies up till the test
but keep in mind that i might be sitting there for 30mins to maybe an hr n a half

plz dont tell me to search the site cuz i have been and its helped me quite a bit all this is for is to make sure im heading in the right path w/this

any tips would help
but ima go practice for a lil bit and check back on here