Is she doing it on purpose?

[ruthc86]

At nearly 5 months old now we have pretty much house trained Millie on the popping outside (still struggling with her peeing indoors) but she knows to let us know when she wants to go for a poo by run up and down the hallway wimpering so we always let her out when she does it and 95% of the time she goes 5% of the time she just wants us to get up and doesn't actually need to go lol.
My question is though is even when she's been outside and everything is fine if she is left for a couple of minutes in the hallway she cries like mad and poos on the floor (its tile so easy to clean) but she doesn't like being left alone unless she is in her crate and this is just for a minute or 2 while I nip upstairs.
Is she doing this on purpose like when she knows she's being nàyghty on purpose because she wants attention while we are watching something on tele? Is there a way to try stop her?