a)

On April 13, 2026, Sentinel issued a promissory note in the principal amount of $60,000 to a related party, the Company’s President and CEO, which matured on June 12, 2026 and accrues interest at 6% per annum. As this note was not repaid upon maturity, effective that date it began to accrue a penalty at the rate of $15,000 per month. The Company has accrued interest and penalty totaling $919 and zero in connection with this note as of June 30, 2026 and December 31, 2025, respectively, and classified such amounts in the Accounts Payable and Accrued Expenses.

b)

On April 30, 2026, Sentinel issued a promissory note in the principal amount of $15,000 to a related party, the Company’s President and CEO which matured on June 29, 2026 and accrues interest at 6% per annum. As this note was not repaid upon maturity, effective that date it began to accrue a penalty at the rate of $15,000 per month. The Company has accrued interest and penalty totaling $781 and zero in connection with this note as of June 30, 2026 and December 31, 2025, respectively, and classified such amounts in Accounts Payable and Accrued Expenses.

Notes payable due to a related party