Complex sentence: When she finds a trail of blood there, she realized the Colonel has also been killed by Rehan and immediately radios for help, and gets in touch with Tyagi, who tells her to stop Rehan at any cost.
Split into simpler sentences: When she finds a trail of blood there, she realized the Colonel has also been killed by Rehan and immediately radios for help. She gets in touch with Tyagi, who tells her to stop Rehan at any cost.