SOLUTION - Read this:
The syringe is an item in your pack. You need to enter melee range of one of the Sandworms right outside the building. Make sure the Sandworm is targeted by you and that it is alive and uninjured. In Melee range you can right click on the syringe in your pack and select "use". This will immediately draw a sample (you will see a message in the middle of the screen telling you so). Once the sample is taken, you can kill the Sandworm normally and move on to the next. You will need 5 total.
|Careful Where You Poke|
|Mission Items||Sandworm Syringe|
Careful Where You Poke
Paging Dr. Corman
In Plain Sight
1. Take 5 Sandworm samples
MissionTommy Newton in Watchtower wants you to use the syringe in your pack to take samples from adult sandworms near town.
Tommy Newton: I want to learn more about what makes these sandworms tick. Dr. Lafferty has agreed to process some blood work, but he's understandably squeamish about going face-to-maw with the subjects themselves.
Player:I take it you want ME to jab them with a needle?
Tommy Newton: Man, that's some nasty smelling stuff.
Player:I wouldn't use it as deodorant.
Fragrant as it might be,, I think it'll still be useful to Dr. Lafferty.